While uncomplicated type 2 diabetes mellitus (T2DM) is already associated with an impaired exercise capacity, the presence of other comorbidities appears to further worsen exercise capacity in T2DM. Common diabetic comorbidities such as hypertension, arterial stiffness, cardiovascular disease, systolic dysfunction, diastolic dysfunction, and diabetic nephropathy are all associated with worse exercise capacity in T2DM. Benefits of exercise training programs for those with T2DM and certain comorbidities (e.g., hypertension, increased arterial stiffness, or post-myocardial infarction) have been shown to include improved exercise capacity. Further study is warranted to determine the specific benefits and risks of exercise training in subpopulations of T2DM such as those with T2DM and either congestive heart failure or microvascular complications of diabetes.